TypeError: path must be a string

I followed the directions
When I type in the command below I get the error.

node app.js nodejs.config.js
[2] 26443
server:~/nodejs/mysite$ fs.js:549
return binding.open(pathModule._makeLong(path), stringToFlags(flags), mode);
^

TypeError: path must be a string
at TypeError (native)
at Object.fs.openSync (fs.js:549:18)
at Object.fs.readFileSync (fs.js:397:15)
at Object.server.start (/usr/lib/node_modules/drupal-node.js/lib/server.js:74:15)
at Object. (/usr/lib/node_modules/drupal-node.js/app.js:15:8)
at Module._compile (module.js:409:26)
at Object.Module._extensions..js (module.js:416:10)
at Module.load (module.js:343:32)
at Function.Module._load (module.js:300:12)
at Function.Module.runMain (module.js:441:10)